U.S. Pat. No. 4,228,277 discloses associative water-soluble nonionic cellulose ethers of the so called associative type. They contain as a modifying substituent a C.sub.10 to C.sub.24 long chain alkyl group which may be introduced by reacting a water-soluble cellulose ether and a suitable amount of the corresponding C.sub.10 to C.sub.24 epoxide.
In EP-A-390 240 associative nonionic cellulose ethers are described which may contain hydrophobic substituents of the formula ##STR2##
where R is a hydrophobic group containing 8-36 carbon atoms, A is an alkylenoxy group having 2-3 carbon atoms and n is a number from 0 to 6. In Example F the publication discloses an ethyl hydroxyethyl cellulose ether containing the hydrophobic substituent ##STR3##
The degree of substitution of this group is 0.016.
It has now been found that the properties of the prior art nonionic cellulose ethers can be improved by the present nonionic cellulose ethers which have improved thickening effects, especially in paint compositions.